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Increased telomerase activity and vitamin D supplementation in overweight African Americans.

ABSTRACT: We aimed to investigate whether vitamin D supplementation modulates peripheral blood mononuclear cell (PBMC) telomerase activity in overweight African Americans.A double blind, randomized and placebo-controlled clinical trial (#NCT01141192) was recently conducted.African-American adults were randomly assigned to either the placebo, or the vitamin D group (60,000?IU per month (equivalent to ~2000?IU per day) oral vitamin D3 supplementation). Fresh PBMCs were collected from 37 subjects (18 in the placebo group and 19 in the vitamin D group), both at baseline and 16 weeks. PBMC telomerase activity was measured by the telomeric repeat amplification protocol.Serum 25 hydroxyvitamin D levels increased from 40.7±15.7 at baseline to 48.1±17.5?nmol?l(-1) at posttest (P=0.004) in the placebo group, and from 35.4±11.3 at baseline to 103.7±31.5?nmol?l(-1) at posttests (P<0.0001) in the vitamin D group. In the vitamin D group, PBMC telomerase activity increased by 19.2% from baseline (1.56±0.29 absorbance reading unit (AU)) to posttest (1.86±0.42 AU, P<0.0001). The significance persisted after controlling for age, sex and body mass index (P=0.039). PBMC telomerase activity in the placebo group did not change from baseline (1.43±0.26 AU) to posttest (1.46±0.27 AU, P=0.157).Vitamin D supplementation significantly increased PBMC telomerase activity in overweight African Americans. Our data suggest that vitamin D may improve telomere maintenance and prevent cell senescence and counteract obesity-induced acceleration of cellular aging.

SUBMITTER: Zhu H

PROVIDER: S-EPMC3826782 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature

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Increased telomerase activity and vitamin D supplementation in overweight African Americans.

Zhu H H Guo D D Li K K Pedersen-White J J Stallmann-Jorgensen I S IS Huang Y Y Parikh S S Liu K K Dong Y Y

International journal of obesity (2005) 20111011 6

<h4>Objective</h4>We aimed to investigate whether vitamin D supplementation modulates peripheral blood mononuclear cell (PBMC) telomerase activity in overweight African Americans.<h4>Design</h4>A double blind, randomized and placebo-controlled clinical trial (#NCT01141192) was recently conducted.<h4>Subjects and methods</h4>African-American adults were randomly assigned to either the placebo, or the vitamin D group (60,000 IU per month (equivalent to ~2000 IU per day) oral vitamin D3 supplementa ...[more]

PMID: 21986705

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Project description:BACKGROUND:A critical need exists to better understand the physiological sequel of vitamin D supplementation in obese individuals and African Americans. The aim was to comprehensively evaluate dose- and time-responses of a panel of vitamin D biomarkers to vitamin D supplements in this population. METHODS:We conducted a 16-week randomized, double-blinded, and placebo-controlled clinical trial. Seventy overweight/obese African Americans (age 13-45 years, 84 % females) with 25-hydroxyvitamin D [25(OH)D] concentrations ?20 ng/mL were randomly assigned to receive a supervised monthly oral vitamin D3 of 18,000 IU (~600 IU/day, n?=?17), 60,000 IU (~2000 IU/day, n?=?18), 120,000 IU (~4000 IU/day, n?=?18), or placebo (n?=?17). RESULTS:There were significant dose- and time-responses of circulating 25(OH)D, 1,25-dihydroxyvitamin D [1,25(OH)2D], and intact parathyroid hormone (iPTH), but not fibroblast growth factor-23 (FGF-23), phosphorus and urine calcium to the vitamin D supplements. The mean 25(OH)D concentrations in the 2000 IU and 4000 IU groups reached ?30 ng/mL as early as 8-weeks and remained at similar level at 16-weeks. The increase of 25(OH)D was significantly higher in the 4000 IU group than all the other groups at 8-weeks. The increase of 1,25(OH)2D was significantly higher in the 2000 IU and 4000 IU groups than the placebo at 8-weeks. Only the 4000 IU compared to the placebo significantly reduced iPTH at 8- and 16-weeks. CONCLUSIONS:Our RCT, for the first time, comprehensively evaluated time- and dose- responses of vitamin D supplementation in overweight/obese African Americans with suboptimal vitamin D status. Circulating 25(OH)D, 1,25(OH)2D, and iPTH, but not FGF-23, phosphorus and urine calcium, respond to vitamin D supplementation in a time- and dose-response manner. By monthly dosing, 2000 IU appears to be sufficient in achieving a 25(OH)D level of 30 ng/mL in this population. However, importantly, 4000 IU, rather than 2000 IU, seems to suppress iPTH. If replicated, these data might be informative in optimizing vitamin D status and providing individualized dosing recommendation in overweight/obese African Americans. TRIAL REGISTRATION:ClinicalTrials.gov number: NCT01583621, Registered on April 3, 2012.

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Increased telomerase activity and vitamin D supplementation in overweight African Americans.

Publications

Increased telomerase activity and vitamin D supplementation in overweight African Americans.

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